Telephone system



F. M. SLOUGH.

TELEPHONE SYSTEM.

APPLICATION FILED 1AN.8. I916.

Patented Nov. 4, 1919.

FRANK M. SLOUGH, OF ELYRIA, OHIO, ASSIGNOR, BY MESNE ASSIGNMENTS, TO STROMBERG-CARLSON TELEPHONE MFG. (30., OF ROCHESTER, NEW YORK,

CORPORATION OF NEW YORK.

Specification of Letters Patent.

Patented Nov. 4, 1919.

Application filed. January 8, 1916. Serial No. 70,895.

To all whom it may concern:

Be it known that I, FRANK M. SLoUGH, a citizen of the United States, and a resident of Elyria, in the county of Lorain and State of Ohio, have invented certain new and useful Improvements in Telephone Systems; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to improvements in telephone systems, and more particularly central energy systems. There is a certain type of central energy system which has come to be known as the automatic disconnect system and in which means are provided for CliSCOIlnGCting the terminals of the link conductors from the main portions of the link conductors at the time the conversation is terminated or between that time and the time when another conversation is initiated. In systems of this type in use hitherto,'so far as I am aware, recalls have been effected by operating the line lamp through the raising or lowering of the switch-hook at the subscribers station.

One of the objects of my invention is to provide means for initiating a recall in an automatic disconnect telephone system, which, can be effected by the operation of the subscribers apparatus in the same manner as it is operated to initiate a call, thereby eliminating the jiggling of the hook-switch. Other objects of my invention and the invention will probably be better understood from a description of an embodiment of the invention.

The drawing shows a diagrammatic representation of an embodiment of my invention. Referring now to the drawing and to the embodiment illustrated therein at I is shown a telephone line which, for convenience, will here be referred to as the calling line. At II is shown a second telephone line, which, for convenience, will be here referred to as the called line. At III is shown a main station. At this main station there is shown means for connectin the telephone lines together, such as lin conductors, shown in this embodiment as a cord circuit and which will, for convenience, be referred to as a cord circuit. Any desired number of stations may be connected to the line I.

At the station B the receiver is shown at v E, the transmitter at F and the hook-switch at Gl The line leads to the main station, where it terminates in switchin terminals, here illustrated as jacks J and The line relay is shown at H, the cut-ofi relay at I and line lamps at K and K,. The link conductorswitching terminals, here shown as plugs, are shown at Pthe answering plug, and at P the calling plug. A subscribercontrolled relay is shown at L which is also known among some engineers as a supervisory relay. The sleeve relay is shown at M; the automatic disconnect relay is shown at N; the operators set is shown at O; the ringing machine at Q; the called subscribercontrolled or supervisory relay is shown at R; a second sleeve relav is shown at S; a signal lamp is shown at T and a commutator is shown at U. The ringing key is shown at V and the listening key at W.

Briefly, the operation of the system is as I follows: The subscriber at B initiates a call,

causing the energization of the line relay H, which in turn causes the energization of the line lamps K and K which are located so as to attract the attention of different operators. Assuming that the operator controlling the cord A inserts the plug P into the jack J, the cut-off relay I and the sleeve relay M will be actuated over a circuit including the switch 12. The cut off relay I will disconnect the line lamp and relay from the line, extinguishing the line lamps, in a'well known manner. The relay M opens a switch 3tt in the circuit of the lamp T, preventing the present actuation of the same and closes a switch 56 in a branch of its circuit which passes through the switch 1-2. At the time the plug P was inserted into the jack J, the subscriber-controlled relay L was actuated, closing a switch 78 and completing a circuit for the relay M through the switches 5-6 and 78, independently of the branch through the switch 12. The operator then actuates the listening key W and learns that it is the subscriber at D that is wanted. The plug P is then connected to the called line, whereupon the relay S is actuated, opening the switch l2 and closing the switch 29, for a purpose later'to be described. The

. switch 11 will also be closed, completing a circuit for the lamp X. The ringing key V is then operated, connecting the ringing machine Q, to the line and calling the subscriber at D.

When the subscriber at D responds, the relay R is actuated, opening the switch 12-13 and extinguishing the lamp at X. With the apparatus in this condition, the conversation takes place, and at the termina-' tion of the conversation, the subscribers restore their substation sets to normal, interrupting the circuits of the relays L and R. The deenergization of the relay R will cause a reenergization of the lamp X. The deenergization of the relay L restores the apparatus to the condition in which it is shown in the drawing, opening the switch 78 and causing the deenergization of the relays M and I, closing the switch 1415 in the circuit of the disconnect relay N.

Now, should the subscriber at B initiate a recall, it will only be necessary to take the receiver from the hook, which rises and completes the circuit of the relay L which closes a switch 16-17, which completes a circuit for the lamp T through the commutator U and-the switches .3lc and 1011. This will cause a flashing or intermittent action of the lamp T in the presence of the operator who controls the cord A and attract her attention.

When the subscriber at B initiates a recall, a circuit will be completed through the relay I, reenergizing the same. Such circuit will include the switches 29 and 14L18. The energizat-ion of the relay I will prevent the line lamps K and K being lighted, so that there will be no cause for any other operator pluggingin to answer the recall, thereby limiting the recall signal to the operator whose cord is already. connected to the line desiring the recall. This is especially convenient and saves time, especially when the subscriber at B desires a reconnection with the subscriber at D, which very frequently happens.

However, should there be no recall and a second operator desires a connection with the line I, the insertion of a plug of her cord into a multiple jack of this line will cause the automatic actuation of the relay N and the disconnection of the cord A from the line I. This is effected by completing a circuit for the relay N through the switches 1415, 2!) and the relay M of the cord of the second operator.

, A more particular description of the operatlon of the embodiment of my invention lamps K and K burn in-the presence of the operators, one of whom answers the call. Assuming that 1t is the operator who con trols the cord A,she answers by inserting the plug P into the jack J, the tip contact 57, the sleeve contact 58 and ring contact 59 of the plug engaging respectively with the tip spring 60, sleeve spring 61 and ring 62 of the jack. The operation of the device PJ completes the following circuits: 50 I636259conductor 63--21relay Mbattery 6 lto ground 65. Both the relays I and M will be energized. The relay 1 will attract its armatures 49 and 43, open ing the switches 4l8t9 and el-3 l4, disconnecting the line relay and lamps from the line and causing the lamps to cease to burn.

The relay M is actuated, opening the switch 3-4 in the circuit of the lamp T and preventing the same from being actuated at this stage of the operation. The relay M also attracts its armature 6, closing the switch 56 for a purpose presently to be described.

The actuation of the device J-P when the hook-switch at the substation is closed will also complete a circuit for the relay L as follows: L-7071-switch 7:27357 6046-EFGi5- 61 58- 7%- 75- 76Lbattery 77conductor 78. The rela L will attract its armature 16 o )ening the switch 7 916 and closing the switch 16-17. This operation, however, will be without result at this stage, because the switch 3-l is now open. The relay L will also attract its armature 14, opening the switch 14l15, which will also be without result at this stage of the operation. The attraction of 14 will also close the switch 14: 18, which will be Without result at this stage of the operation. The relay L will also attract the armature 8, closing the switch 78 and completing a: circuit through the relay -l independent of'the switch l-2. This circuit will be as follows; 6564tM conductor 80- 8- 7 5 6- 63-130 ground through the relay 1. The operator now operates the switch W, connects her set with the cord circuit and learns the subscriber that is desired.- \Ve will assume that D is wanted. The plugP, is inserted into the jack 5,, the respective contacts of vthe jack and. plug engaging in the same manner as explained in connection with the plug P and jack J. A circuit is completed for the relay S as follows: ground 81battery 82-Sconductor S3-through the plug P, and jack J the called line cutoff relay I to ground. The relay S attracts its armature 2, opening the switch 1-2 and closing a switch 29, neither of which has any effect at this stage-of the operation, except to open the contacts in the old and now unimportant circuit of the relay M, which as has been explained, is now energized through thecircuit containing the switch 5-6. The relay S closes the switch 10-11 in the circuitof the lamp X, which is as follows: 81.821110-12-13-Xto ground at 90. The ringing key V is then operated and the subscriber at D is called.

The response of the subscriber at D completes the circuit of the relay R in the same manner as was described for the relay L, except that the circuit will be over the called line and through the called subscribers set, instead of over the calling line and the set of the calling subscriber, as in the case of the relay L.

The actuation of R opens a switch 1213 in the circuit of X and causes this lamp to go out. Conversation then takes place, and at the termination of the conversation, the receivers are restored to the hooks, opening the hook-switches at the respective stations and opening the circuits of the relays L and R, whereupon the armatures controlled by these relays are restored to the condition in which they are shown in the drawing. The lamps X and T will then burn,the lamp X over the circuit previously described, and the lamp T over the following circuit: 818211109113T1679 to ground at 92. Assuming now that the subscriber at B desires to make a recall before the plugs are withdrawn from the jacks, (it should here be explained that the operators do not always withdraw the plugs immediately upon the termination of conversation, because, for one reason, they may be busy with other matters. It also frequently happens, especially in the case of one of the subscribers being a private branch exchange, that the subscriber desires another connection with the same called. subscriber)assuming now that the subscriber at G again removes his receiver from the hook-switch, the hook-switch will be closed and the relay L energized, as previously described, and as previously described, the armatures 16, 8 and 14: will be attracted, opening the switches 16-79 and 14 15 and closing the switches 16-17, 78 and 1418. The relay I will be energized over the following circuit: 50I63'625963291 l -18777892. The relay I will prevent the actuation of the lamps K and K thereby avoiding the recall signal being given to other operators than the one whose plug is already inserted into the jack of the line I. The circuit of the lamp T will now include the interrupter U, which will cause the intermittent flashing of this lamp to advise the operator controlling the cord A that a recall is desired, whereupon she connects her set with the cord and proceeds to set up a connection as before.

Should another operator desire to use the line I, a plug of one of her cords may be inserted into a multiple jack, for example, into the jack J and if the plug P has not been withdrawn from the jack J and the line I is idle, a circuit will be completed for the automatic disconnect relay N as follows: ground at 100N15-149263 596263 -101lO2M- battery 103 ground 104:. The relay N will be energized, disconnecting the cord A from the plug P by opening the switches 7273 and Wit-75 and leaving the line I free of the cord A. WVhen the plugs are withdrawn from the jacks, the apparatus will be restored to normal.

I have shown this particular form and these particular details for the purpose of better explaining my invention, it being obviousthat numerous and extensive departures may be made from the form and de tails illustrated without departing from the spirit of the invention.

I claim:

1. In a telephone system, the combination of a main station, a calling telephone line, substation apparatus including a switch on the calling line, line signaling mechanism for said telephone line, a cut-off relay for said telephone line adapted when energized to disassociate said line signaling mechanism from the line, a cord circuit at the mainstation, a switch for connecting the cord circuit to the telephone line, a circuit for said cut-off relay controlled by said switch and completed, when said switch is operated, to cause the energization of the cut-off relay, a second relay controlled by the switch at the subscribers station and contacts in the circuit of the cut-off relay controlled by said subscriber-controlled relay, said second relay causing the opening of the circuit and the deenergization of the cutoff relay when the subscriber retires and recompleting such circuit when the subscriber initiates a recall to cause a second energiza- "by associated with the link conductors;

supervisory relays connected in said talking strands, a controlling relay in the operating strand associated with the calling line, means independent of the calling subscrib ers relay and the operators key and con tacts controlled thereby to causevan initial operation of said controlling relay when connection is made between the link circuit and calling line, and means under the control of the calling subscribers supervisory relay to restore said controlling relay to normal.

3. In a telephone system, the combination of a calling line, a called line, a link circuit, link conductors for said link circuit comprising talking and operating strands, a supervisory relay in the talking strand leading to the calling line, a controlling relay in the operating strand associated with the calling line, a cutoff relay for said calling line, a circuit for said controlling relay including said cut-oil relay, said circuit including contacts of said supervisory relay and contacts of said controlling relay.

4:. In a telephone system, the combination of a calling line, a called line, a link circuit, link conductors for said link circuit comprising talking and operating strands, a supervisory relay in the talking strand lead ing to the calling line, a controlling relay in the operatingstrand associated with the calling line, a cut-off relay for said calling line and a circuit for said controlling relay including said cut-oil relay, said circuit including contacts of said supervisory relay and contacts of said controlling relay, said circuit being established when connection is made with a calling line and disestablished when said supervisory relay is restored to normal'to give a disconnect signal.

5. In a telephone system, the combination of a calling line, a called line, a link circuit, link conductors for said link circuit comprising talking and operating strands, a supervisory relay in the talking strand leading to the calling line, a controlling relay in the operating strand associated with the calling line, a cut-off relay for said calling line, and a circuit for said controlling relay including said cut-on" relay, said circuit including contacts of said supervisory relay and contacts of said controlling relay, switching means to establish said circuit when connection is made with a calling line, I

a controlling relay in the operating strand associated with the. called line, switching means to operate said controlling relay when connection is made with a called line, a switch of said last named controlling relay to initially establish the circuitof said first named controlling relay, said switch preventing said circuit from being reestablished after said supervisory relay is restored to normal to give a disconnect signal.

6. In a telephone system, the combination of a calling line, a called line, a link circuit, link conductors for said link circuit comprising talking and operating strands, a supervisory relay in the talking strand leading to the calling line, a controlling relay in the operating strand associated with the calling line, a out-ofl relay for said calling line, and a circuit for said controlling relay including said cut-ofli relay, said circuit including contacts of said supervisory relay and contacts of said controlling relay, switching means to establish said circuit when connection is made with a calling line, a controllingrelay in the operating strand associated with the called line, switching means to operate said controlling relay when connection is made with a called line, a switch of said last named controlling relay to initially establish the circuit of said first named controlling relay, said switch preventing said circuit -from being reestablished after said supervisory relay is restored to normal to give a disconnect signal, and an alternate circuit for said cut-ofl' relay including switch contacts operated by said supervisory relay when said supervisory relay is subsequently operated.

In witness whereof, I have signed my name this 29th day of December, 1915.

FRANK M. SLOUGHQ Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

